It is known that the zooplankter Daphnia induces colonies in the alga Scenedesmus. As Daphnia grazes on Scenedesmus, it has been postulated that colony formation represents an algal defense mechanism. This induction of Scenedesmus coenobia/colonies by Daphnia could be associated with a substance exuded by the animals that acts as a specific infochemical (kairomone) for Scenedesmus. However, the...

Ecotoxicological endpoints based on behavioral traits (e.g., predator avoidance, feeding, and locomotion) may be more sensitive and give more insights into patterns of sublethal toxicity than survivorship tests. In this study, the density-dependent grazing rate of Daphnia pulex pre-exposed to p,p'-dichlorodiphenyldichloroethylene (DDE) (insecticide metabolite) and glyphosate (herbicide), via wa...

The complete amino acid sequence of ferredoxin isolated from a green alga, Scenedesmus species, was determined by analyses of tryptic and chymotryptic digests, and cyanogen bromide cleavage of the S-carboxymethylcysteinylferredoxin. The total number of amino acid residues is 96, one less than for the higher plant ferredoxins. It is the first chloroplasttype ferredoxin found lacking in tryptopha...

The green alga Scenedesmus is known for its phenotypic plasticity in response to grazing risk. However, the benefits of colony formation induced by infochemicals from zooplankton should come with costs. That is, a tradeoff in benefit-to-cost ratios is likely under complex environmental conditions. In this study, we hypothesized that the coexistence of Scenedesmus and its competitors decreases t...

U. C. Vothknecht* and D. Dörnemann Fachbereich Biologie/Botanik, Philipps-Universität Marburg, Karl-v.-Frisch-Straße, D-35032 Marburg, Bundesrepublik Deutschland Z. Naturforsch. 50c, 789-795 (1995); received June 16/August 28, 1995 C5-Pathway, Glutamyl-tRNAglu-Synthetase (E.C.6.1.1.17), Misacylation of tRNAglu, Amidotransferase, Scenedesmus obliquus In a previous paper we described the purifica...

The potential biomass yield per phosphorus and lipid/triglyceride (TAG) accumulation properties of seven microalgal species: Scenedesmus sp. LX1, Chlorella ellipsoidea YJ1, Chlorella vuglaris, Chlorella sorokiniana, Chlorella pyrenoidosa, Dunaliella primolecta and Haematococcus pluvialis were investigated. Among the tested species, Scenedesmus sp. LX1 obtained the smallest minimal phosphorus co...

The aim of this work was to study the potential of the two phototrophic microorganisms, both isolated from Ebro Delta microbial mats, to be used as bioindicators and immobilizers of chromium. The results obtained indicated that (i) the Minimum Metal Concentration (MMC) significantly affecting Chlorophyll a intensity in Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 was 0.25 µM and 0.75 µM, ...